Mobile communication systems are being developed to provide communication services to users while the users are on the move. Mobile communication systems, starting with voice communication services, are now able to offer high-speed data communication services.
For example, mobile communication systems for high-data communication services have evolved from the 3rd Generation Partnership Project (3GPP) system to the Long Term Evolution (LTE) system. The LTE system enables high-data communication services at a speed up to 100 Mbps.
The LTE system is now progressing to the LTE-Advanced (LTE-A) system for increased transmission speed. A representative technique as newly adopted for the LTE-A system is carrier aggregation.
Carrier aggregation is a technology in which a user equipment (UE) communicates signals using multiple forward (or downlink) carriers and multiple backward (or uplink) carriers. As an example, the LTE-A system is highly likely to adopt intra-evolved Node B (eNB) carrier aggregation.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.